This application claims priority of Japanese Application No. 2000-198915, filed Jun. 30, 2000, the entire contents of which are hereby incorporated by reference.
The present invention relates to color filter arrays for solid-state image devices or liquid crystal display devices, and to a method for producing the same.
As a color filter array formed on a device such as a solid-state image device or a liquid crystal display device, there has been known a color filter array (2) constituted of a red filter layer (R), a green filter layer (G), and a blue filter layer (B) formed so as to be adjoining to each other in the same plane of a substrate (1) (FIG. 1). In the color filter array (2), the filter layers (R), (G), (B) are arranged in a striped pattern (FIG. 2) or a lattice-like pattern (mosaic) (FIG. 3).
A variety of processes for producing such color filter arrays have been proposed. Among them, the so-called xe2x80x9ccolor resist methodxe2x80x9d is in wide practical use. In the color resist method, the patterning is effected by exposing a photosensitive resin composition comprising colorants to light and developing, and the patterning is repeated in sequence for the required number of times.
As the photosensitive resin composition which is employed in the color resist method, those employing pigments as colorants are in wide use. However, such pigments are not suitable for the formation of fine or minute patterns, for they are granular and do not dissolve in developers, and developing residue is generated.
As a photosensitive resin composition for obtaining a finely patterned color filter array, a photosensitive resin composition employing dyes as colorants has also been known. For example, Japanese Patent Application Laid-Open No. 6-75375 discloses a negative photosensitive resin composition comprising dyes, and Japanese Patent Publication No. 7-111485 discloses a positive photosensitive resin composition comprising 10 to 50%, on a dry weight basis, of a dye soluble in the solvent used in the positive photosensitive resin composition. (Hereinafter, xe2x80x9cJP-A-xe2x80x9d is used for indicating Japanese Patent Application Laid-Open, and xe2x80x9cJP-B-xe2x80x9d is used for indicating Japanese Patent Publication.) Colorants comprised in photosensitive resin compositions used for producing color filter arrays, such as those described above, are required to have the following two properties.
(1) Good spectroscopic characteristics, that is, showing sufficient absorption within the predetermined visible ray region and no unnecessary absorption in the other region.
(2) Good light fastness, that is, no burn-in due to the decolorization of dyes under normal operating conditions However, none of the dyes employed in conventional photosensitive resin compositions used for forming a blue filter layer has both of the above-described two properties.
The inventors of the present invention have made intensive and extensive studies to develop a color filter array having a blue filter layer having good spectroscopic characteristics as well as good light fastness. As a result, they have found that the use of a specific dye realizes the formation of a blue filter layer satisfactory both in spectroscopic properties and light fastness. The present invention was accomplished based on this finding.
The invention provides a color filter array having a blue filter layer on a substrate wherein the blue filter layer comprises a triallylmethane dye (hereinafter, referred to as xe2x80x9cdye (I)xe2x80x9d) showing its absorption maximum at a wavelength within the range of from 550 to 650 nm; and has a transmittance at a wavelength of 450 nm of 70% or more and that at 650 nm of 5% or less.
The invention also provides a process for producing the color filter array.